General guide to frost free refrigeration and repairs
Before you start to read through this article, the first rule to follow is that if you are able and prepared to carry out any maintenance on your appliance, please remember to disconnect your fridge freezer from the power source. This is a critical action as it may well save your life! Sounds dramatic but it is true, trying to repair any electrical appliance without disconnecting from the main supply is stupid in itself, but when you add in the possibility of water that you encounter in your fridge freezer it can become positively dangerous.
Unfortunately, manufacturers do not provide any kind of manual or instructions for you to follow when carrying out a repair. No amount of searching on the internet will help you either, so unless you are fully competent and confident in your ability, it would be a much safer option to call in the services of a qualified engineer. Although this will cost you more than if you did the work yourself, modern fridge freezers are not only complicated but also delicate, and it would be very easy for you to puncture the compartment wall or even the pipework. One of which could be terminal for your appliance, and the other could mean the expense of an engineer having to regas the unit for you.
Understanding the basic principles
In order for a frost free fridge freezer to operate, either free-standing or American style, the following needs to happen, otherwise it will fail to work:
- fans must be free of ice
- Airflow is able to circulate around the compartment to ensure food is correctly cooled, or frozen, depending on which action you require
The frost free fridge freezer works on the air circulating and chilling the food, as opposed to the falling air principle used by the non-frost free appliances.
All frost free fridge freezers have at least one heating fan which will be activated when frost crystals form within the freezer compartment. The fan melts the frost that has formed and the resulting water is channelled to a drainhole at the bottom of the compartment. Some manufacturers have provided a second heating fan sited at this drainhole to ensure it is not blocked by ice, which will in even more ice being formed.
If you have a problem with your appliance, you should check these areas in the freezer if you find the temperature is not at the right level, either too high or too low.
Cold air is drawn into the fridge compartment from the freezer by a fan, especially in the American style fridge freezers. There could also be a fan operated flap drawing air from the freezer into the fridge.
This is obviously where to start looking if the fridge is not cool enough as no cold air will be pulled into the fridge compartment if the flap fails. If the flap is still working, your next port of call will be the fan as if this is faulty, no cold air will be pushed into the fridge compartment.
Most fan motors are fairly simple, and can easily be checked by a multimeter, if you have one. If you don’t have an open circuit, there is probably no issue with the motor. Unfortunately it is generally quite expensive to replace the motor, and some of them are in very awkward positions, and some are not accessible at all.
Evaporators and Defrost Heaters
The defrost heater is also a simple component and is located around the freezer evaporator. Again you can check the heater with a multimeter.The downside of this simple component is that it is generally wrapped around the evaporator, which can mean that it is very difficult or even impossible to replace.
With great care the heater can be removed from the evaporator and replaced with a new part. However, it is also a delicate operation and you may end up damaging either or both of the components. This will obviously result in a much higher outlay, probably increasing your bill tenfold! It may be one of those occasions when speaking to a qualified engineer may end up the cheaper option.
An electronic thermistor is the sensor which controls the current temperature inside both the fridge and freezer compartments. They can be replaced with care if you are able to identify the thermistor as the problem. However, it is well to note that they are fairly fault free in general use, but this does not mean they never go wrong.
As the name implies, this is the main control for the unit, and will read the temperatures provided by the themistors.
One of the best things about them is that they are generally not the reason for any fault with your fridge freezer. It is probably a good idea not to look at the controller first but to work through all the other reasons for the problem, before you come back to the controller.
There is always the chance that your make and model fridge freezer is subject to a problem with the controller, but it is still a good idea to check everything else first.
Non-electronic defroster controls
On some older and less expensive appliances, there will be a defrost timer instead of the electronic controller. If this component fails, be sure to identify the correct part for your specific make and model, otherwise you will have problems in maintaining the correct temperature, and it could end up either too cold or too warm.
You may also own a make and model that is controlled by a component known as a defrost terminator and/or initiation thermostat. These operate exactly as they sound, they will activate the start and completion of the defrost operation.
Like any other component, these can fail and will need to be replaced in order to ensure your food is stored at the correct temperatures.
Checklist of faults
Listed below you will find assistance with fault diagnosis. Obviously this does not cover each and every problem you may encounter, but it should help to get your started to identify a fault:
Overfreezing/Ice Build Up
- Check thermistors or thermostats are working
- Ensure fan motors are working and are not coated In ice.
- Check the defrost heater is working
You will also need to identify the type of ice, clear and smooth or powdery like snow. The clear ice indicates water is leaking and then freezing in place. You will need to find the reason for the leak. In most cases you will more than likely need to call in a qualified engineer if it is not a simple issue, as this could indicate you have a major problem.
If its powdery ice, you should check the fit and seal of the door, as this will generally indicate that air is leaking from the appliance. You will need to check the door shuts tightly, if there is a gap you may need to look at the door hinges and make sure the door is level. If the seal is flattened or bruised in places, you could try warming the seal with a hair dryer for a few minutes, as this may bring it back into the correct shape. If you find any splits in the seal, you will need to replace the seal as soon as possible, this should be both cheap and easy to do.
Fridge and/or Freezer Compressor
The compressor is an electronic motor which compresses the gas and, under pressure, is pumped around the pipework operating the fridge freezer. This is a sealed unit and contains only a very small amount of gas, which does not need to be topped up.
If the compressor does not run, there is a possibility the starter relay is faulty. This is attached to the side of the compressor. If you hear a click-buzz sound from the compressor and it does not start when it should, this is an indication that it is faulty.
You may well have an electronic unit with a display, and you should check to see if a fault code is being displayed. However, fault codes are not that easy to decipher, and you may just get an indication of where the fault is located.
You may be surprised to learn that you could see a ‘not cooling’ fault code, even though your freezer is actually over freezing. This is because if the freezer does not defrost correctly, the evaporator will over freeze leading to an ice build up, which could jam the fan.
Before you attempt any repair to your appliance, please bear in mind that all fridge freezers are different depending on the make and model, even though the general principles are the same, the way they operate or parts are located is purely down to the design. You must, therefore, be absolutely sure you know what you are doing before you start.
Any damage caused by you will negate the terms of your Guarantee or Extended Warranty, and may result in you having to pay for any resulting repairs, as they will be deemed to be self-inflicted.
As a lot of the electronically controlled fridge freezers are highly technical, it may be worth your while at least speaking to a qualified engineer about your particular problem first. This should help you to decide whether you will do the work yourself, or ask the engineer to carry out this work on your behalf.